In automation technology, field transmitters are frequently used, which serve for recording and/or influencing process variables. Examples of such field transmitters are level measuring instruments, mass flowmeters, pressure gages, temperature gages etc., which record the corresponding process variables—level, mass flow, pressure and temperature. Process variables are influenced using “actuators” which, in the form of valves, for example, influence the flow of a liquid in a pipeline section.
The field transmitters are generally connected to a central control and engineering system which controls the whole process flow and permits direct access to the individual field transmitters. The control system evaluates and monitors the measured values for the various process variables and drives the appropriate actuators accordingly in order to influence the process.
Data are transmitted between field transmitter and control system on the basis of the known international standards for field buses, such as Hart, Foundation Fieldbus, Profibus, CAN etc.
Automation installations today frequently comprise a multiplicity of different field transmitters from a very wide variety of manufacturers. Before startup, and also during operation, settings need to be made on the field transmitters. These settings frequently have to be made in situ. The individual field transmitter manufacturers each provide different configuration programs for this purpose.
It is an extremely complex and time consuming matter for the user to master the different programs, including the different operating philosophies. Setting the parameters of individual field transmitters or configuring particular field transmitter groups is extremely complex and expensive in an automation installation having a multiplicity of field transmitters, on account of the various communication interfaces and the protocols required.
The configuration, operation and maintenance of a field transmitter in an automation installation should be a much simpler matter.
One aspiration is a plug and play system for field transmitters.
Various field transmitter manufacturers have therefore merged to form PROFIBUS Nutzerorganisation e.V. [PROFIBUS User Organization, a registered association] in order to simplify operation of the field transmitters. The field transmitter manufacturer develops a specific software module for each of his field transmitters, which is supplied to the customer together with the field transmitter. This software module encapsulates all the data and functions of the respective field transmitter. In principle, the field transmitter is a black box, so that third parties cannot access inhouse know-how. In addition, the manufacturer of the unit may also provide his own aspect with this software module. This means that the user interface of the field transmitter always appears the same to the user, irrespective of the runtime environment. The application program used for configuring, operating and maintaining various field transmitters accesses the respective field transmitter software module using a defined interface. One option for the interface specification is indicated in Profibus Guideline—Order No. 2.162, last updated November 2000, obtainable from PROFIBUS Nutzerorganisation e.V., Karlsruhe, to whose content specific reference is made.
Each field transmitter manufacturer supplies his field transmitter together with particular software modules representing the standard functionalities of a field transmitter.
Besides these standard functionalities, the user also requires expansion functionalities, however, particularly in the area of foresighted maintenance, in the installation documentation etc.
These functionalities cannot be called using the normal application program.